spi/qspi: cleanup pm_runtime error check.

clean up pm_runtime error check in accordance with rest of the check in
the driver.
Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-ti-qspi.c

@@ -161,7 +161,7 @@ static int ti_qspi_setup(struct spi_device *spi)
 			qspi->spi_max_frequency, clk_div);
 
 	ret = pm_runtime_get_sync(qspi->dev);
-	if (ret) {
+	if (ret < 0) {
 		dev_err(qspi->dev, "pm_runtime_get_sync() failed\n");
 		return ret;
 	}